Bugs in Space


News Photo
Harmless microorganisms may become dangerous in space.

 

Microorganisms are unavoidable in spacecrafts and their presence has, at times, been a source of problems. Astronauts spend months in the same quarters, breathe recycled air and drink recycled water; conditions that create a bacterial breeding ground. Additionally, the space environment has been shown to suppress the human immune system, making the body more susceptible to infection. Further, weightlessness and higher levels of radiation may increase the mutation rate in bacteria. This could result in the emergence of some organisms more resistant to antibiotics or in the change of normally harmless organisms into pathogenic life forms.

Because of unidentified effects of space on bacteria and the immune system, we do not know which organisms will cause problems. A group of researchers led by Drs. George E. Fox and Richard C. Wilson from the Department of Biology and Biochemistry at the University of Houston and Maia Larios-Sanz, then at the University of Houston and currently at the University of St. Thomas, have developed a technique to determine the approximate identity of organisms in space.

Their approach is phylogenetic, i.e., the approximate identity of a bacterium is based on the similarity of its DNA to known bacteria. Organisms whose DNA sequences are closely matched are more closely related than organisms whose DNA sequences are less similar. Fox, Willson, Larios-Sanz and their collaborators have developed a method to identify the DNA sequences that are diagnostic of small groups of bacteria.

Current detection systems mandate that one tests for an exact organism. If a problem organism is similar but not identical to the organism one is testing for, the test will show up negative. However, with the system developed by the University of Houston researchers, astronauts would be able to pinpoint an organism's rough taxonomic affiliation and significantly narrow down the possibilities of its identity. Once the device identifies the problem organism, scientists can predict the bacterial source, like a faulty air filter or a water purifier, and fix the defective instrument for future missions.

Because of limited laboratory space and chemical availability in spacecrafts, the University of Houston researchers are designing an easy-to-use monitoring method. Astronauts would filter the air or water, or swab a surface, to obtain the bacterial sample, and then they would test the sample for high levels of certain organisms that would indicate contamination. The tool will provide an early warning that the air or water purification system might not be working properly. The routine monitoring system and the bacterial identification device will help astronauts stay healthy during their time in space.

Larios-Sanz M, Kourentzi KD, Warmflash D, Jones J, Pierson DL, Willson RC, and Fox GE. 2007.16S rRNA beacons for bacterial monitoring during human space missions. Aviation, Space and Environmental Medicine 78:A43A47.